Technologies for displaying a stereoscopic video without requiring special glasses are known (e.g., see Patent Literatures (PTL) 1 to 3, and Non-patent Literature (NPL) 1). These technologies need a component, such as a parallax barrier (a disparity barrier) or a Lenticular lens, set up in front of a display panel on an observer side, such as an LCD panel, a plasma display panel (PDP), and an organic EL panel.